In a Biodiesel Production plant water can sometimes enter the system along with the waste grease. If the right systems are not in placed to remove this water, the product quality will be compromised and unwanted glycerin will be created instead of biodiesel. As was the case for one of BurrowX’s previous clients.
BurrowX recommends before the feed can enter the pre-treatment section, the water content needs to be reduced to less than 0.2 wt%. It is very common for the feed to have excessive water, and appropriate measures must be taken to either reduce the usage of that feed stock, or eliminate the water upstream. Please read our recommendation on Biodiesel Feed Composition here.
First, free water can be removed by gravity separation. The feed will sit in a heated storage tank for 24 hours, during which the oil and water will separate and the water (which is heavier than oil) will settle to the bottom. The tank is heated to make the oil phase thinner, thus speeding up the separation process. Now, the water content is approximately 0.4 wt%, still double the recommended amount.
After the free water has been removed by gravity separation, the oil phase should be moved to an evaporator to remove any entrained water. The evaporator can be heated and agitated for 8 hours. During this time, additional water will be evaporated, lowing the total water content to <0.2 wt%.
Lowering the water content results in the process being able to handle a higher FFA content. Although the target is 1% FFA, the process will be able to handle deviations in that specification if the water content is low enough.
For assistance troubleshooting your Biodiesel Production Plant or implementing the recommendations above please contact us here